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1.
Plant regeneration in Arachis pintoi was obtained via two developmental pathways: organogenesis and somatic embryogenesis. Organogenic callus cultures were initiated
from pieces of leaf on MS medium supplemented with NAA or 2,4-D in combination with BA, KIN or 2iP. The most suitable combination
for plant regeneration through organogenesis was an initial medium composed of 10 mg/l NAA+1 mg/l BA followed by transfer
of the callus to a shoot induction medium (MS+1 mg/l BA). Rooting of regenerated shoots was readily achieved by culture on
MS+0.01 mg/l NAA. Embryogenic callus cultures were initiated from pieces of leaf on MS medium supplemented with PICL in combination
with KIN, ZEA, BA or 2iP, and the most suitable combinations were 20 mg/l PICL+1 mg/l BA or 2iP. When pieces of embryogenic
callus were subcultured on MS+1 mg/l BA, somatic embryos were differentiated and developed further into well-developed plants
in MS+1 g/l AC followed by MS medium devoid of plant growth regulators.
Received: 29 April 1999 / Revision received: 24 November 1999 / Accepted: 18 December 1999 相似文献
2.
Callus induction and plant regeneration were studied in 15 cultivars of the facultative apomictic species Poa pratensis L. (Kentucky bluegrass).The tissue culture responses of mature seeds and immature inflorescences were compared. Murashige and Skoog's (MS) medium, supplemented with 2 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D) was used for callus induction and maintenance. Plants could be regenerated from compact and friable callus on MS medium devoid of 2,4-D. Plants were recovered from 14 cultivars at a high frequency (up to 79% of the callus cultures) when young inflorescences were used as the explant material and from only 3 cultivars, at a low frequency (up to 3%), with seeds. Somatic embryos were observed in callus cultures of many cultivars. Fully developed germinating somatic embryos were occasionally observed. Plant regeneration appeared to take place both via somatic embryogenesis and organogenesis. Plants were generally green but albino shoots developed at a low frequency from friable callus.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- MS
Murashige and Skoog's (1962) medium
- IAA
indole-3-acetic acid
- N6
medium of Chu et al. (1975) 相似文献
3.
Summary Indirect somatic embryogenesis, encapsulation, and plant regeneration was achieved with the rare rhoeophytic woody medicinal
plant Rotula aquatica Lour. (Boraginaceae). Friable callus developed from leaf and internode explants on Murashige and Skoog (MS) medium with 0.45 μM 2,4-dichlorophenoxyacetic, acid (2,4-D) was most effective for the induction of somatic embryos. Subculture of the callus
onto half-strength MS medium with the same concentration of 2,4-D resulted in highly embryogenic callus. Suspension culture
was superior to solid medium culture for somatic embryogenesis. Embryogenic callus.during subsequent transfer to suspension
cultures of half-strength MS medium having 0.23 μM 2,4-D induced the highest number of somatic embryos (a mean of 25.6 embryos per 100 mg callus) and the embryos were grown
up to the torpedo stage. Transfer of embryos to half-strength MS basal solid medium allowed development, of 50% of the embryos
to the cotyledonary stage. Of the cotyledonary embryos, 90% underwent conversion to plantlets on the same medium. Encapsulated
cotyledonary embryos exhibited 100% conversion to plantlets. Ninety-five percent of the plantlets established in field conditions
survived, and were morphologically identical to the mother plant. 相似文献
4.
R. V. Sairam C. Wilber J. Franklin B. Smith J. Bazil R. Hassel D. Whaling K. Frutiger C. A. Blakey R. Vierling S. L. Goldman 《In vitro cellular & developmental biology. Plant》2002,38(5):435-440
Summary A protocol for high-frequency callus, somatic embryogenesis, and plant regeneration for Tripsacum is described. Plants were regenerated from complete shoot meristems (3–4 mm) via organogenesis and embryogenesis. In organogenesis,
the shoot meristems were cultured directly on a high cytokinin medium comprising 5–10 mgl−1 (22.2–44.4 μM) 6-benzyladenine (BA). The number of multiple shoots varied from six to eight from each meristem. The time required for production
of plants from organogenesis was rapid (4–6 wk). In contrast, callus was induced on an auxin medium and continuously cultured
on an auxin medium for production of somatic embryos. Prolific callus with numerous somatic embryos developed within 3–4 wk
when cultured on an auxin medium containing 5 mgl−1 (22.6μM), 2,4-dichlorophenoxyacetic acid (2,4-D). The number of shoots induced varied from two to five per callus. Regardless of
the cultivars used, the frequency of callus induction and plant regeneration was between 48% and 94%. The seed germination
procedures also were modified and resulted in a maximum of 60–80% seed germination. Finally, the rate of T-DNA transfer to
complete shoot meristems of Tripsacum was high on the auxin medium and was independent of whether super-virulent strains of Agrobacterium were used or not. 相似文献
5.
High-frequency plant regeneration via somatic embryogenesis and organogenesis and in vitro flowering of regenerated plantlets in Panax ginseng 总被引:4,自引:0,他引:4
W. Tang 《Plant cell reports》2000,19(7):727-732
The morphogenesis ability of light yellowish globular callus derived from cotyledons of mature zygotic embryos of Panax ginseng was investigated. The optimal media for somatic embryogenesis and shoot organogenesis were MS medium containing 0.5 mg l–1 2,4-dichlorophenoxyacetic acid, 0.1 mg l–1 6-benzyladenine (BA), and 500 mg l–1 lactoalbumin hydrolysate, and SH medium supplemented with 0.5 mg l–1 α-naphthaleneacetic acid, 0.1 mg l–1 BA, and 500 mg l–1casein hydrolysate. The influences of glucose, mannose, fructose, and sorbose in the media on somatic embryogenesis and shoot
organogenesis were revealed as differences in the numbers of somatic embryos and adventitious shoots per gram of morphogenic
callus. The best regeneration of somatic embryos was obtained on medium containing glucose, with a mean of 8.7 somatic embryos
per gram of callus. The best regeneration of shoots was observed on medium containing fructose, with an average of 12.2 adventitious
shoots per gram of callus. Of the somatic embryos 95% were converted into regenerated plantlets, and 100% of adventitious
shoots rooted to form regenerated plantlets. Regenerated plants were successfully established in soil. Flowering was observed
in 5.7% of the regenerated plants derived from shoot organogenesis and in 1.4% of the regenerated plants derived from somatic
embryogenesis.
Received: 1 December 1998 / Revision received: 13 September 1999 / Accepted: 20 September 1999 相似文献
6.
The effect of auxins, time exposure to auxin and genotypes on somatic embryogenesis from mature embryos of wheat 总被引:3,自引:0,他引:3
Mikhail Filippov Dmitry Miroshnichenko Darya Vernikovskaya Sergey Dolgov 《Plant Cell, Tissue and Organ Culture》2006,84(2):100192-100201
The effects of different factors on the embryogenesis and plant regeneration from mature embryos of Russian spring and winter
genotypes were studied. Embryogenic callus induction was achieved on MS medium supplemented with different concentrations
of 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) or Dicamba (3,6-dichloro-o-anisic acid). Although all auxins were able to induce callus from explants with high frequency (98–100%), Dicamba was more
effective for the induction of embryogenic callus (21.8–38.3%). Maximum embryogenic callus formation and high number of regenerated
plants were observed at 12 mg l−1 of Dicamba. The time exposure to Dicamba (7, 14, 21 and 28 days) had a significant effect on efficiency of somatic embryogenesis.
When contact of explants with callus induction medium was increased from 7 to 21 days the rate of somatic embryogenesis and
number of regenerated plants per embryogenic callus gradually increased from 13.0 to 38.4% and 3.6 to 8.0%, respectively.
Supplement of additional auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), and naphthaleneacetic acid (NAA)) to callus
induction medium with Dicamba had a positive effect on the rate of embryogenic callus formation, while the average number
of regenerated shoots was not affected. The best rate of somatic embryogenesis was observed at the addition of 0.5 mg l−1 IAA with Dicamba (61.0%). The optimum combination of Dicamba and IAA increased the efficiency of somatic embryogenesis and
plant regeneration from seven spring and winter wheat genotypes, thought overall morphogenic capacity was still genotype dependent. 相似文献
7.
P. Jha C. B. Yadav V. Anjaiah V. Bhat 《In vitro cellular & developmental biology. Plant》2009,45(2):145-154
An efficient in vitro plant regeneration protocol through somatic embryogenesis and direct shoot organogenesis has been developed for pearl millet
(Pennisetum glaucum). Efficient plant regeneration is a prerequisite for a complete genetic transformation protocol. Shoot tips, immature inflorescences,
and seeds of two genotypes (843B and 7042-DMR) of pearl millet formed callus when cultured on Murashige and Skoog (MS) medium
supplemented with varying levels of 2,4-dichlorophenoxyacetic acid (2,4-D; 4.5, 9, 13.5, and 18 μM). The level of 2,4-D, the
type of explant, and the genotype significantly effected callus induction. Calli from each of the three explant types developed
somatic embryos on MS medium containing 2.22 μM 6-benzyladenine (BA) and either 1.13, 2.25, or 4.5 μM of 2,4-D. Somatic embryos
developed from all three explants and generated shoots on MS medium containing high levels of BA (4.4, 8.8, or 13.2 μM) combined
with 0.56 μM 2,4-D. The calli from the immature inflorescences exhibited the highest percentage of somatic embryogenesis and
shoot regeneration. Moreover, these calli yielded the maximum number of differentiated shoots per callus. An efficient and
direct shoot organogenesis protocol, without a visible, intervening callus stage, was successfully developed from shoot tip
explants of both genotypes of pearl millet. Multiple shoots were induced on MS medium containing either BA or kinetin (4.4,
8.8, 17.6, or 26.4 μM). The number of shoots formed per shoot tip was significantly influenced by the level of cytokinin (BA/kinetin)
and genotype. Maximum rooting was induced in 1/2 strength MS with 0.8% activated charcoal. The regenerated plants were transferred
to soil in pots, where they exhibited normal growth. 相似文献
8.
Summary High-frequency somatic embryogenesis and plant regeneration was achieved on callus derived from leaf (petiole and lamina)
and internode explants of Centella asiatica L. Growth regulators significantly influenced the frequency of somatic embryogenesis and plant regeneration. Calluses developed
on Murashige and Skoog (MS) medium fortified with 4.52 μM 2,4-dichlorophenoxyacetic acid (2,4-D) or 5.37 μM α-naphthaleneacetic acid (NAA), both with 2.32 μM kinetin (Kn), were superior for somatic embryogenesis. Callus developed on NAA and Kn-supplemented medium favored induction
and maturation of embryos earlier compared to that on 2,4-D and Kn. Embryogenic callus transferred from NAA and Kn-supplemented
medium to suspension cultures of half-strength MS medium with NAA (2.69 μM) and Kn (1.16 μM) developed a mean of 204.3 somatic embryos per 100 mg of callus. Embryogenic callus transferred from 2,4-D and Kn subsequently
to suspension cultures of half-strength MS medium with 2,4-D (0.45 μM) and Kn (1.16 μM) developed a mean of 303.1 embryos per 100 mg of callus. Eighty-eight percent of the embryos underwent maturation and conversion
to plantlets upon transfer to half-strength MS semisolid medium having 0.054 μM NAA with either 0.044 μM BA or 0.046 μM Kn. Embryo-derived plantlets established in field conditions displayed morphological characters identical to those of the
parent plant. 相似文献
9.
Jinfeng Lü Rong Chen Muhan Zhang Jaime A. Teixeira da Silva Guohua Ma 《Journal of plant physiology》2013
Camellia nitidissima Chi (Theaceae) is a world-famous economic and ornamental plant with golden-yellow flowers. It has been classified as one of the rarest and most endangered plants in China. Our objective was to induce somatic embryogenesis, shoot organogenesis and plant regeneration for C. nitidissima. Three types of callus (whitish, reddish and yellowish) were induced from immature cotyledons on improved woody plant medium (WPM) with different plant growth regulators (PGRs). Among the callus, whitish callus was induced by 4.5 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and reddish and yellowish callus were induced by strongly active cytokinins, thidiazuron (TDZ) or 6-benzylaminopurine (BAP), singly or combined with weakly active auxin, α-naphthaleneacetic acid (NAA). The embryogenic callus could differentiate into somatic embryos, nodular embryogenic structures (large embryo-like structures) or adventitious shoots depending on the PGR used in WPM. BAP was best for adventitious buds and zeatin was best for somatic embryogenesis while kinetin (Kt) was best for the formation of nodular embryogenic structures. The three regeneration pathways often occurred in the same embryogenic callus clumps. Most shoots (80.0%) developed roots in WPM supplemented with 24.6 μM IBA and 0.3 μM NAA while 47.5% of somatic embryos could germinate directly and develop into plantlets on induction medium supplemented with 0.9 μM BAP and 0.1 μM NAA. The nodular embryogenic structures could be sub-cultured and cyclically developed in one of two differentiation pathways: shoot organogenesis or somatic embryogenesis. Plantlets derived from shoot buds rooted and somatic embryos germinated when transplanted into soil in a greenhouse; 66.7% of plantlets from shoot culture and 78.6% of plantlets from somatic embryos survived after 8 weeks’ acclimatization. 相似文献
10.
11.
Myung Jin Oh Hye Ryun Na Hong-Keun Choi Jang Ryol Liu Suk Weon Kim 《Plant biotechnology reports》2008,2(1):87-92
An improved protocol for high frequency plant regeneration via somatic embryogenesis from zygotic embryo-derived cell suspension
cultures of watershield (Brasenia schreberi) was developed. Zygotic embryos formed pale-yellow globular structures and white friable callus at a frequency of 80% when
cultured on half-strength MS medium supplemented with 0.3 mg l−1 2,4-D. However, the frequency of formation of pale-yellow globular structures and white friable callus decreased slightly
with increasing concentrations of 2,4-D up to 3 mg l−1, where the frequency reached ~50% of the control. Cell suspension cultures from zygotic embryo-derived white friable callus
were established using half-strength MS medium supplemented with 0.3 mg l−1 2,4-D. Upon plating of cell aggregates on half-strength MS basal medium, approximately 8.3% gave rise to somatic embryos
and developed into plantlets. However, the frequency of plantlet development from cell aggregates was sharply increased (by
up to 55%) when activated charcoal and zeatin were applied. Regenerated plantlets were successfully transplanted to potting
soil and grown to normal plants in a growth chamber. The distinctive feature of this study is the establishment of a high
frequency plant regeneration system via somatic embryogenesis from zygotic embryo-derived cell suspension cultures of watershield,
which has not been previously reported. The protocol for plant regeneration of watershield through somatic embryogenesis could
be useful for the mass propagation and transformation of selected elite lines. 相似文献
12.
Summary An efficient system for the regeneration of plants from protoplasts was developed in Alstroemeria. Friable embryogenic callus (FEC) proved to be the best source for protoplast isolation and culture when compared with leaf
tissue and compact embryogenic callus. Protoplast isolation was most efficient when FEC was cultured under vacuum for 5 min
in an enzyme solution consisting of 4% cellulase, 0.5% Driselase and 0.2% Macerozyme, followed by culture for 12–16h in the
dark at 24°C. Cell wall formation and colony formation were better in a liquid medium than on a semi-solid agarose medium.
Micro-calluses were formed after 4 wk of culture. Ninety percent of the micro-calluses developed into FEC after 12wk of culture
on proliferation medium. FEC cultures produced somatic embryos on a regeneration medium and half of these somatic embryos
developed shoots. Protoplast-derived plants showed more somaclonal variation than vegetatively propagated control plants. 相似文献
13.
Genetic variability of somatic embryogenesis in tissue cultures of sugar beet breeding lines 总被引:1,自引:0,他引:1
Golovko A 《T?Sitologii?a i genetika》2001,35(6):10-17
Genetic variability of callus initiation and plant regeneration has been investigated among three sugar beet genotypes. It was found that TDZ has a genotype-independent effect on callus initiation and is responsible for more than a two-fold increase in the friable callus induction rate and more than a three-fold increase in the shoot regeneration rate from this callus. Along with the genotype-independent organogenesis, regeneration from callus occasionally went through the process of somatic embryogenesis in a highly genotype-specific manner. Despite fast and uncontrollable conversion of embryos to normal plants, it was possible to select and maintain repetitive embryogenic culture without loosing regeneration and root formation capabilities. Extensive experimenting with medium composition and culture conditions resulted in an optimal medium for maintenance of repetitive embryos. Comparing with BAP, low concentrations of TDZ provide higher level of adventitious shoot formation and do not induce vitrification of tissues. 相似文献
14.
Plant regeneration from 2-month-old callus cultures derived from immature leaves of 7-day-old aseptic seedlings and mature embryos of the African wild rice Oryza longistaminata was achieved at 20% and 100% frequency, respectively. The morphogenic potential of the embryo-derived calluses dropped from 100% at the third subculture to 12.5 % at the 12th subculture. Five-month-old morphogenic calluses were used to establish a fast-growing suspension culture which, when plated onto semisolid medium, still retained its ability to regenerate plantlets 9 months after initiation. Histological analyses demonstrated that late plant regeneration from established callus and suspension cultures occured through organogenesis, although some embryogenesis events may have taken place during initiation of these cultures.Abbreviations 2,4-D
2,4-dichlorophenoxyacetic acid
- NAA
-naphthalenacetic acid
- BAP
6 benzylaminopurine
- PAS
Periodic acid shiff 相似文献
15.
Efficient callus induction and plant regeneration from mature embryo culture of winter wheat (Triticum aestivum L.) genotypes 总被引:14,自引:0,他引:14
Immature and mature embryos of 12 common winter wheat (Triticum aestivum) genotypes were cultured in vitro to develop an efficient method of callus formation and plant regeneration from mature embryo
culture, and to compare the responses of both embryo cultures. Fifteen days after anthesis, immature embryos were aseptically
dissected from seeds and placed with the scutellum upwards on a solid agar medium containing the inorganic components of Murashige
and Skoog (MS) and 2 mg/l 2,4-dichlorophenoxyacetic acid (2,4-D). Mature embryos were moved slightly in the imbibed seeds.
The seeds with moved embryos were placed furrow downwards in dishes containing 8 mg/l 2,4-D for callus induction. The developed
calli and regenerated plants were maintained on 2,4-D-free MS medium. Plants regenerated from both embryo cultures were vernalized
and grown to maturity in soil. Regenerated plantlets all maintained the hexaploid chromosome number. A strong genotypic effect
on the culture responses was found for both explant cultures. Callus induction rate, regeneration capacity of callus and number
of plants regenerated were independent of each other. Mature embryos had a high frequency of callus induction and regeneration
capacity, and therefore, being available throughout the year, can be used as an effective explant source in wheat tissue culture.
Received: 4 February 1997 / Revision received: 1 April 1997 / Accepted: 5 May 1997 相似文献
16.
Chun-Lai Zhang Dong-Fang Chen Marie Kubalakova Jian Zhang Nigel W. Scott Malcolm C. Elliott Adrian Slater 《Plant Cell, Tissue and Organ Culture》2008,93(2):209-221
Efficient regeneration via somatic embryogenesis (SE) would be a valuable system for the micropropagation and genetic transformation
of sugar beet. This study evaluated the effects of basic culture media (MS and PGo), plant growth regulators, sugars and the
starting plant material on somatic embryogenesis in nine sugar beet breeding lines. Somatic embryos were induced from seedlings
of several genotypes via an intervening callus phase on PGo medium containing N6-benzylaminopurine (BAP). Calli were mainly induced from cotyledons. Maltose was more effective for the induction of somatic
embryogenesis than was sucrose. There were significant differences between genotypes. HB 526 and SDM 3, which produced embryogenic
calli at frequencies of 25–50%, performed better than SDM 2, 8, 9 and 11. The embryogenic calli and embryos produced by this
method were multiplied by repeated subculture. Histological analysis of embryogenic callus cultures indicated that somatic
embryos were derived from single- or a small number of cells. 2,4-dichlorophenoxyacetic acid (2,4-D) was ineffective for the
induction of somatic embryogenesis from seedlings but induced direct somatic embryogenesis from immature zygotic embryos (IEs).
Somatic embryos were mainly initiated from hypocotyls derived from the cultured IEs in line HB 526. Rapid and efficient regeneration
of plants via somatic embryogenesis may provide a system for studying the molecular mechanism of SE and a route for the genetic
transformation of sugar beet. 相似文献
17.
Summary An efficient regeneration system was developed by culturing immature cotyledons and embryo axes of Arachis hypogaea L. cv. Georgia Green on Murashige and Skoog basal medium (MS) supplemented with various concentrations of thidiazuron (TDZ;
1, 5, 10, and 15 μM). Highly morphogenic callus was produced from 100% of the explants comprising the cotyledon with attached embryo axis when
cultured in the dark on 10 μM TDZ. Upon excision and continued culture in the dark on 10 μM TDZ, morphogenic callus grew repetitively during monthly subcultures and retained its regeneration potential. For organogenesis,
a gradual reduction in TDZ concentration and exposure to light were necessary before transfer to MS basal medium. Inclusion
of indole-3-butyric acid in liquid MS medium favored rooting of recovered shoots. A distinct feature of this investigation
is the induction of highly morphogenic callus by TDZ and regeneration of morphologically normal, fertile peanut plants after
8 months of callus subculture. 相似文献
18.
J. Vijaya Kumar B. D. Ranjitha Kumari G. Sujatha Enrique Castaño 《Plant Cell, Tissue and Organ Culture》2008,93(1):85-96
The present study describes a system for efficient plant regeneration via organogenesis and somatic embryogenesis of safflower
(Carthamus
tinctorius L.) cv. NARI-6 in fungal culture filtrates (FCF)-treated cultures. FCF was prepared by culturing Alternaria carthami fungal mycelia in selection medium for host-specific toxin production. Cotyledon explants cultured on callus induction medium
with different levels of FCF (10–50%) produced embryogenic callus. In organogenesis, 42.2% microshoots formed directly from
embryogenic callus tissues in plant regeneration medium with 40% FCF. Isolated embryogenic callus cultured on embryo induction
medium containing 40% FCF induced 50.2% somatic embryogenesis. Embryo germination percentage was decreased from 64.5 to 28
in embryo maturation medium containing 40% FCF. However, nine plantlets from organogenesis and 24 plantlets from somatic embryogenesis
were selected as FCF-tolerant. Alternaria carthami fungal spores (5 × 105 spores/ml) sprayed on the leaves of FCF-tolerant plants showed enhanced survival rate over control plants, which plants were
more susceptible to fungal attack. The number of leaf spot lesions per leaf was decreased from 3.4 to 0.9 and their lesion
length was also reduced from 2.9 to 0.7 mm in organogenic derived FCF-tolerant plants over control. In somatic embryo derived
FCF-tolerant plants, the number of lesions was decreased from 3.1 to 0.4 and the lesion size was also reduced to 2.7–0.5 mm
when compared to the control. This study also examined antioxidant enzyme activity in FCF-tolerant plants. Catalase (CAT)
activity was slightly decreased whereas peroxidase (POD) activity was increased to a maximum of 42% (0.19 μmol min−1 mg−1 protein) from organogenesis and 47% (0.23 μmol min−1 mg−1 protein) from embryogenesis in FCF-tolerant plants. Superoxide dismutase (SOD) activity was also increased to 17% (149 U
mg−1 protein) and 19.5% (145 U mg−1 protein) in FCF-tolerant plants derived from organogenesis and somatic embryogenesis when compared with control plants. 相似文献
19.
Simple hormonal regulation of somatic embryogenesis and/or shoot organogenesis in caryopsis cultures of Pogonatherum paniceum (Poaceae) 总被引:1,自引:1,他引:0
Wenguo Wang Xiaoguang Zhao Guoqing Zhuang Shenghua Wang Fang Chen 《Plant Cell, Tissue and Organ Culture》2008,95(1):57-67
Pogonatherum paniceum (Poaceae) is a perennial plant with good potential for eco-recovery and ornamental function. This study presents in vitro
culture systems of simple hormonal regulation of somatic embryogenesis and shoot organogenesis from mature caryopses. Mature
caryopses of P. paniceum were grown on Murashige and Skoog medium with 3% sucrose (w/v) and various concentrations or combinations of 2,4-dichlorophenoxyacetic
acid (2,4-D), α-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP). Morphological development was analyzed by light
microscope after histological sectioning. Four types of callus were induced by different concentrations of 2,4-D. Type I callus
was regenerated via somatic embryogenesis; type II callus failed to produce any regeneration; type III callus had both somatic
embryogenesis and shoot organogenesis capacities; and type IV callus only displayed shoot organogenesis capacity. Regarding
hormone combinations used in this study, NAA only induced type IV callus and BAP only induced direct multiple shoot formation.
The combinations of 2,4-D and NAA induced type III callus. Several of the regeneration pathways were simply controlled by
one or two kinds of plant hormones. The established systems will be helpful for further research on the developmental mechanism
of switch between somatic embryogenesis and shoot organogenesis. 相似文献
20.
The study was carried out to establish in vitro culture conditions for plant regeneration of tef, Eragrostis tef (Zucc.) Trotter. Mature seeds of two Ethiopian varieties, DZ-01-354 and DZ-01-196, were used to initiate callus cultures
on Murashige and Skoog (MS) medium with different auxins. Four- and 8-week-old calli induced on a medium with 2.0 mg/l 2,4-dichlorophenoxyacetic
acid (2,4-D) were subcultured onto various media to induce somatic embryogenesis. Compact, nodulated, embryogenic callus was
observed after transfer onto MS-callus proliferating (CP) medium. Embryogenic tissue appeared on soft and amorphous callus
and developed into somatic embryos during a subsequent subculture to MS embryo-promoting (EP) media. Various growth regulator
combinations were tested in CP and EP media to obtain a high efficiency of somatic embryo formation. The highest frequency
of calli forming somatic embryos (56.1–68.3%) was observed when CP media with 2.0 or 4.0 mg/l 2,3,5-triiodobenzoic acid were
employed and then cultures were transferred to EP media with 0.5 mg/l 2,4-D and 0.5 mg/l kinetin followed by 0.5 mg/l indole-3-acetic
acid and 0.5 mg/l N6-benzyladenine. Plant development from somatic embryos was obtained on MS medium supplemented with 1.0 mg/l gibberellic acid.
On average, 71.2% of calli displaying somatic embryos converted into plants. Regenerated plants were successfully transferred
to soil. Neither chlorophyll-deficient plants nor morphological variants were found among regenerants. All regenerated plants
were fertile.
Received: 9 May 1997 / Revision received: 25 September 1997 / Accepted: 3 January 1998 相似文献